Operating systems

Instavue extracts the Instaviz diagrams from the user's iPhone or iPod
Touch backups. The user can then choose to print the diagrams or export
them to any of these vector and bitmap formats: BMP, EPS, GIF, Graphviz,
JPEG, PNG, PostScript, SVG, TIFF, Visio VDX, or VML. Mac users can also
export to these additional formats: JPEG2000, OpenEXR, Photoshop, PDF,
Quickdraw, Silicon Graphics or TGA. Windows users can also export to the
EMF (Enhanced Metafile) format.

yEd is a powerful diagram editor which can be used to quickly create diagrams manually or import external data for analysis and auto-magically arrange even large data sets by just pressing a button.
You can use yEd to quickly create flow charts, BPMN and UML diagrams, organization charts, mind maps, Entity Relationship diagrams, and many other kinds of diagrams, graphs, and networks.
Choose from a wide range of highly sophisticated layout algorithms to automatically arrange diagrams in no time.
An intuitive and visually appealing user interface makes creating diagrams fun.
Once a diagram has been created, it's easy to save, print, or export it to popular formats like PDF, SWF, EMF, SVG, JPEG, GIF, PNG, or HTML image maps.

code2flow is an experimental script which sweeps through your project source code, looking for function definitions, then does another sweep, looking for where those functions are called. It connects the dots and presents you with a flowchart estimating the functional structure of your program. It is especially useful for untangling spaghetti code and getting new developers up to speed. code2flow is experimental and meant to provide a rough overview of the structure of simple projects. Source code which is just a little esoteric will break this. Even with normal code, there are many known limitations and many outright bugs.